Actuator-link assembly manufacturing method, actuator-link assembly designing method, and actuator-link assembly

ABSTRACT

In a material determining step, the material constituting an actuator and the material constituting a link are determined such that at least one of the materials contains fiber reinforced plastic. In a computing step, a computation model that defines the relationship between a control surface, the actuator, and the link is used to compute the change in gain margin with the change in a rigidity ratio, which is the ratio of the rigidity of the link to the rigidity of the actuator. The rigidities of the actuator and the link are determined in a rigidity determining step based on a result of the above-described computation, the shapes of the actuator and the link are determined in a shape determining step, and the actuator and the link are formed in a formation step, and are assembled in an assembly step.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No.2010-056922. The entire disclosure of Japanese Patent Application No.2010-056922 is hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an actuator-link assembly including anactuator that can be attached to a control surface of an aircraft or toa horn arm member in order to drive the control surface, and a link thatis connected to the actuator, a manufacturing method for manufacturingthe actuator-link assembly, and a designing method for designing theactuator-link assembly.

2. Description of Related Art

An aircraft is provided with control surfaces that are formed as movingsurfaces (flight control surfaces) and are configured as an aileron, arudder, an elevator, and the like. As an actuator for driving such acontrol surface and a link that is connected to this actuator, thosedisclosed in JP H5-97095A and JP 562-165007A are known. With theactuator-link assemblies disclosed in JP H5-97095A and JP 562-165007A,the actuators are provided as a hydraulically driven cylinder mechanismthat can be attached to a control surface or a horn arm member attachedto the control surface, and the links are coupled pivotably to theactuator and the control surface.

The actuator-link assemblies for driving a control surface of anaircraft as disclosed in JP H5-97095A and JP S62-165007A are required tohave high strength in order to support the load for driving the controlsurface, and are also required to have high rigidity from the viewpointof suppressing the deformation and ensuring the stability as the controlsystems for driving the control surface. For this reason, when theactuator-link assemblies as disclosed in JP H5-97095A and JP S62-165007Aare designed and also when they are manufactured, a metallic materialsuch as stainless steel or a titanium alloy can be selected as thematerial constituting the actuator-link assemblies from the viewpoint ofensuring the required strength and rigidity. However, since theactuator-link assemblies are made of a metallic material, there is alimit to their weight reduction, and it is difficult to achieve furtherweight reduction in the current situation.

When a titanium alloy is used as the material constituting anactuator-link assembly, a high specific rigidity, which is the rigidityper unit weight, can be ensured, but the specific strength, which is thestrength per unit weight, is reduced. For this reason, ensuring thestrength becomes a constraint, making it difficult to achieve weightreduction. On the other hand, when stainless steel is used as thematerial constituting an actuator-link assembly, a high specificstrength can be ensured, but the specific rigidity is reduced. For thisreason, ensuring the rigidity becomes a constraint, making it difficultto achieve weight reduction.

Therefore, in order to provide an actuator-link assembly that can ensurestrength and rigidity in good balance and achieve weight reduction, itis necessary to design the structure of an actuator-link assembly from apoint of view that is completely different from that of conventionaltechnology. Also, in addition to achieving weight reduction, it isnecessary to ensure strength and rigidity that are equivalent to orgreater than those achieved by the conventional technology.

SUMMARY OF THE INVENTION

In view of the above-described situation, it is an object of the presentinvention to provide an actuator-link assembly that can ensure strengthand rigidity that are equivalent to or greater than those achieved bythe conventional technology while achieving further weight reduction, amanufacturing method of the actuator-link assembly, and a designingmethod of the actuator-link assembly.

According to a feature of an actuator-link assembly manufacturing methodof the present invention for achieving the above-described object, thereis provided an actuator-link assembly manufacturing method formanufacturing an actuator that can be attached pivotably, at one endthereof, to a control surface of an aircraft or to a horn arm memberattached to the control surface in order to drive the control surface,and a link that is coupled to the actuator, the method including: amaterial determining step of determining a material constituting theactuator and a material constituting the link; a computing step ofcomputing a change in gain margin with a change in a rigidity ratio,which is the ratio of the rigidity of the link to the rigidity of theactuator, using a computation model that includes an inertial mass ofthe control surface, a rigidity of the control surface, a rigidity ofthe actuator, and a rigidity of the link as parameters and that definesa relationship between the parameters; a rigidity determining step ofdetermining rigidities of the actuator and the link such that therigidity ratio and the gain margin fall within respective predeterminedranges, based on a computation result obtained in the computing step; ashape determining step of determining shapes of the actuator and thelink such that rigidities of the actuator and the link are set to therigidities determined in the rigidity determining step; a formation stepof forming the actuator and the link into the shapes determined in theshape determining step; and an assembly step of coupling and assemblingthe actuator and the link formed in the formation step, wherein the linkis attached pivotably to a fulcrum shaft for rotatably supporting thecontrol surface, and is also attached pivotably to the other end of theactuator via a pivot shaft, and, in the material determining step, thematerials are determined such that at least one of the materialconstituting the actuator and the material constituting the linkcontains fiber reinforced plastic.

With this configuration, the material constituting the actuator fordriving the control surface and the material constituting the link thatis coupled to the actuator are determined such that at least one of thematerials contains fiber reinforced plastic. Accordingly, it is possibleto achieve an actuator-link assembly that has a significantly smallerspecific gravity (i.e., also has a significantly smaller density), asignificantly greater specific strength and a significantly greaterspecific rigidity than that achieved with a titanium alloy. Further, itis possible to achieve an actuator-link assembly that has asignificantly greater specific strength and a significantly greaterspecific rigidity than that achieved with stainless steel. Also, basedon the computation result obtained using the computation model for thecontrol surface, the actuator, and the link, the rigidities of theactuator and the link are determined such that the rigidity ratio of thelink to the actuator and the gain margin fall within their respectivepredetermined ranges that have been set. Consequently, the rigidity ofthe actuator-link assembly containing fiber reinforced plastic as theconstituent material can be reliably determined to be a level capable ofsufficiently suppressing deformation and ensuring sufficient stabilityas the control system for driving the control surface. Also, the shapesof the actuator and the link are determined such that the rigiditiesdetermined in the above described manner can be set, and the actuatorand the link are formed in the shapes determined in the above-describedmanner. Further, the actuator and the link are coupled and assembled,thus completing the actuator-link assembly. Thus, it is possible tomanufacture an actuator-link assembly that can realize weight reductioncompared with conventional actuator-link assemblies made of metals suchas a titanium alloy and stainless steel, and ensure strength andrigidity that are equal to or greater than those achieved with suchactuator-link assemblies.

Accordingly, with this configuration, it is possible to manufacture anactuator-link assembly that can ensure strength and rigidity that areequal to or greater than those achieved with their conventionalcounterparts, and realize further weight reduction.

According to a first feature of the actuator-link assembly designingmethod of the present invention for achieving the above-describedobject, there is provided an actuator-link assembly designing method fordesigning an actuator that can be attached pivotably, at one endthereof, to a control surface of an aircraft or to a horn arm memberattached to the control surface in order to drive the control surface,and a link that is coupled to the actuator, the method including: amaterial determining step of determining a material constituting theactuator and a material constituting the link; a computing step ofcomputing a change in gain margin with a change in a rigidity ratio,which is the ratio of the rigidity of the link to the rigidity of theactuator, using a computation model that includes an inertial mass ofthe control surface, a rigidity of the control surface, a rigidity ofthe actuator, and a rigidity of the link as parameters and that definesa relationship between the parameters; a rigidity determining step ofdetermining rigidities of the actuator and the link such that therigidity ratio and the gain margin fall within respective predeterminedranges, based on a computation result obtained in the computing step;and a shape determining step of determining shapes of the actuator andthe link such that rigidities of the actuator and the link are set tothe rigidities determined in the rigidity determining step, wherein thelink is attached pivotably to a fulcrum shaft for rotatably supportingthe control surface, and is also attached pivotably to the other end ofthe actuator via a pivot shaft, and, in the material determining step,the materials are determined such that at least one of the materialconstituting the actuator and the material constituting the linkcontains fiber reinforced plastic.

With this configuration, the material constituting the actuator fordriving the control surface and the material constituting the link thatis coupled to the actuator are determined such that at least one of thematerials contains fiber reinforced plastic. Accordingly, it is possibleto achieve an actuator-link assembly that has a significantly smallerspecific gravity (i.e., also has a significantly smaller density), asignificantly greater specific strength and a significantly greaterspecific rigidity than that achieved with a titanium alloy. Further itis possible to achieve an actuator-link assembly that has asignificantly greater specific strength and a significantly greaterspecific rigidity than that achieved with stainless steel. Also, basedon the computation result obtained using the computation model for thecontrol surface, the actuator, and the link, the rigidities of theactuator and the link are determined such that the rigidity ratio of thelink to the actuator and the gain margin fall within their respectivepredetermined ranges that have been set. Consequently, the rigidity ofthe actuator-link assembly containing fiber reinforced plastic as theconstituent material can be reliably determined to be a level capable ofsufficiently suppressing deformation and ensuring sufficient stabilityas the control system for driving the control surface. Also, the designof the actuator and the link is completed upon determination of theirshapes such that the rigidities determined in the above described mannercan be set. Thus, it is possible to design an actuator-link assemblythat can realize weight reduction compared with conventionalactuator-link assemblies made of metals such as a titanium alloy andstainless steel, and ensure strength and rigidity that are equal to orgreater than those achieved with such actuator-link assemblies.

According to a second feature of actuator-link assembly designing methodof the present invention, in the actuator-link assembly designing methodhaving the first feature, the link includes: a pair of linear portionsdisposed alongside each other and each extending linearly; a couplingportion connecting to one end of each of the pair of linear portions onthe same side via a bent portion and extending so as to couple the oneend of each of the pair of linear portions on the same side to eachother; a fulcrum shaft attachment portion that is provided so as toprotrude from a center portion of the coupling portion and that can beattached pivotably to a fulcrum shaft for rotatably supporting thecontrol surface; and an actuator attachment portion that is provided asthe other end of each of the pair of linear portions and that can beattached pivotably to the other end of the actuator via a pivot shaft,and, in the material determining step, the materials are determined suchthat a material constituting the pair of linear portions and thecoupling portion contains fiber reinforced plastic.

With this configuration, in order to stably drive the control surfacevia actuation of the actuator, the link is designed that is formed inthe shape of a portal including the pair of linear portions and thecoupling portion coupling to the pair of linear portions via the bentportions. In the case of a portal-shaped link including bent portions,it is difficult to realize weight reduction, while ensuring strength andrigidity in good balance. However, with this designing method, thematerial constituting the pair of linear portions and the couplingportion of the link is determined to be fiber reinforced plastic, andtherefore it is possible to ensure strength and rigidity in good balanceat a higher level, and to realize significant weight reduction.

According to a third feature of the actuator-link assembly designingmethod of the present invention, in the actuator-link assembly designingmethod having the first feature, the computation model used in thecomputing step defines a relationship between the parameters, as aspring-mass model in which the inertial mass of the control surface, aspring obtained by modeling the rigidity of the control surface, aspring obtained by modeling the rigidity of the actuator, and a springobtained by modeling the rigidity of the link are coupled in series.

With this configuration, the computation model used in the computingstep is configured for the control surface, the actuator, and the linkas a spring-mass model in which the inertial mass and the springsthereof are coupled in series. Accordingly, a computation model for moreaccurately defining the relationship between the parameters of theinertial mass of the control surface, the rigidity of the controlsurface, the rigidity of the actuator, and the rigidity of the link canbe achieved with a simple computation model, based on the actualrelationship between the control surface, the actuator, and the linkthat are coupled in series.

According to a feature of an actuator-link assembly of the presentinvention for achieving the above-described object, there is provided anactuator-link assembly including an actuator that can be attachedpivotably, at one end thereof, to a control surface of an aircraft or toa horn arm member attached to the control surface in order to drive thecontrol surface, and a link that is coupled to the actuator, wherein thelink includes: a pair of linear portions disposed alongside each otherand each extending linearly; a coupling portion connecting to one end ofeach of the pair of linear portions on the same side via a bent portionand extending so as to couple the one end of each of the pair of linearportions on the same side to each other; a fulcrum shaft attachmentportion that is provided so as to protrude from a center portion of thecoupling portion and that can be attached pivotably to a fulcrum shaftfor rotatably supporting the control surface; and an actuator attachmentportion that is provided as the other end of each of the pair of linearportions and that can be attached pivotably to the other end of theactuator via a pivot shaft, and a material constituting the pair oflinear portions and the coupling portion contains fiber reinforcedplastic.

With this configuration, in order to stably drive the control surfacevia actuation of the actuator, the link is provided that is formed inthe shape of a portal including the pair of linear portions and thecoupling portion coupling to the pair of linear portions via the bentportions. In the case of a conventional portal-shaped link that is madeof a metallic material such as a titanium alloy or stainless steel andthat includes bent portions, it is difficult to realize further weightreduction, while ensuring strength and rigidity in good balance.However, with this configuration, a material constituting the pair oflinear portions and the coupling portion of the link contains fiberreinforced plastic. Accordingly, it is possible to achieve anactuator-link assembly that has a significantly smaller specific gravity(i.e., also has a significantly smaller density), a significantlygreater specific strength and a significantly greater specific rigiditythan that achieved with a titanium alloy. Further, it is possible toachieve an actuator-link assembly that has a significantly greaterspecific strength and a significantly greater specific rigidity thanthat achieved with stainless steel. This makes it possible to ensurestrength and rigidity in good balance at a higher level and to realizesignificant weight reduction for an actuator-link assembly. Thus, it ispossible, with this configuration, to realize weight reduction for anactuator-link assembly including a portal-shaped link, compared withconventional actuator-link assemblies made of metals such as a titaniumalloy and stainless steel, and to ensure strength and rigidity that areequal to or greater than those achieved with the conventionalactuator-link assemblies.

It should be appreciated that the above and other objects, and featuresand advantages of the present invention will become apparent from thefollowing description taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an actuator-link assembly accordingto one embodiment of the present invention.

FIG. 2 is a schematic diagram showing a state in which the actuator-linkassembly shown in FIG. 1 is attached to a body of an aircraft, togetherwith a part of the body.

FIG. 3 is a perspective view of the link shown in FIG. 1.

FIG. 4 is a plan view of the link shown in FIG. 3.

FIG. 5 is a side view of the link shown in FIG. 3.

FIG. 6 is a flowchart illustrating an actuator-link assemblymanufacturing method according to one embodiment of the presentinvention.

FIG. 7 is a functional block diagram of a designing apparatus thatperforms a design process of the manufacturing method shown in FIG. 6.

FIG. 8 is a diagram illustrating a computation model used in a computingstep in the design process of the manufacturing method shown in FIG. 6.

FIG. 9 is a graph illustrating a computation result obtained in thecomputing step in the design process of the manufacturing method shownin FIG. 6.

FIG. 10 is a graph illustrating the results of analyzing therelationship between the rigidity ratio and the weight of anactuator-link assembly designed with the design process of themanufacturing method shown in FIG. 6, for varying constitutingmaterials.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, an embodiment for carrying out the present invention willbe described with reference to the accompanying drawings. The embodimentof the present invention can be widely applied to an actuator-linkassembly including an actuator that can be attached to a control surfaceof an aircraft or to a horn arm member in order to drive the controlsurface and a link that is coupled to the actuator, a manufacturingmethod for manufacturing the actuator-link assembly, and a designingmethod for designing the actuator-link assembly.

[Actuator-Link Assembly]

FIG. 1 is a perspective view showing a control surface drive unit 1 thatis provided as a unit for driving a control surface of an aircraft andthat constitutes an actuator-link assembly according to an embodiment ofthe present invention. FIG. 2 is a schematic diagram showing a state inwhich the control surface drive unit 1 is attached to a body 100 of theaircraft, together with a part of the body 100. Examples of aircraftmoving surfaces (flight control surfaces) constituting the controlsurface 102 include an aileron, a rudder, and an elevator. The controlsurface drive unit 1 may also be used as a unit for driving controlsurfaces configured as a flap, a spoiler, and the like.

The control surface drive unit 1 shown in FIGS. 1 and 2 includes anactuator 11 for driving the control surface 102 and a reaction link 12constituting a link of this embodiment that is coupled to the actuator11. As will be described later, the control surface drive unit 1 isdesigned by an actuator-link assembly designing method according to anembodiment of the present invention, and is manufactured by anactuator-link assembly manufacturing method according to an embodimentof the present invention.

The actuator 11 is provided as a hydraulically driven cylindermechanism, and includes a cylindrical cylinder body 13 and a roundbar-shaped rod portion 14 having a circular cross section. The cylinderbody 13 is actuated by supplying and discharging pressure oil to andfrom the inside of the cylinder body 13 using a hydraulic system (notshown) provided in the aircraft (not shown), and the rod portion 14 isactuated such that it is displaced so as to extend or contract from orinto the cylinder body 13. The cylinder body 13 and the rod portion 14are made of stainless steel, for example. The material constituting theactuator 11 is determined by the actuator-link assembly designing methoddescribed below.

At the tip end of the rod portion 14, which is located at one end of theactuator 11, the actuator 11 is attached pivotably to the controlsurface 102 via a hinge portion or the like. At an end of the cylinderbody 13, which is located at the other end of the actuator 11, theactuator 11 is supported relative to a body frame 101 via a supportingmember 103. Further, the actuator 11 is coupled pivotably to thesupporting member 103 (in FIG. 1, the illustration of the couplingbetween the actuator 11 and the supporting member 103 has been omitted).Note that the tip end of the rod portion 14 need not be directlyattached to the control surface 102, and may be attached pivotably to ahorn arm member attached to the control surface 102. In this case, thehorn arm member is configured as a member that is attached to thecontrol surface 102 so as to be pivotable together with the controlsurface 102 (i.e., fixed to the control surface 102), and that iscoupled pivotably to the tip of the rod portion 14 of the actuator 11.Accordingly, the actuator 11 drives the control surface 102 via the hornarm member.

As shown in FIG. 2, the reaction link 12 is attached to the body frame101 of the body 100, and is provided so as to prevent a load applied tothe control surface 102 from directly affecting the body frame 101.Further, as shown in FIGS. 1 and 2, the reaction link 12 is coupled tothe actuator 11, and includes a reaction link body 15, a bearing 16,bushes 17, fastening members 18, and so forth.

FIG. 3 is a perspective view of the reaction link 12. FIG. 4 is a planview of the reaction link 12, and FIG. 5 is a side view of the reactionlink 12. The reaction link body 15 of the reaction link 12 shown inFIGS. 1 to 5 is made of carbon fiber reinforced plastic (CFRP). Also,the reaction link body 15 is formed in the shape of a portal, andincludes a pair of linear portions 19 (19 a, 19 b), a coupling portion20, a fulcrum shaft attachment portion 21, and actuator attachmentportions 22. Note that the reaction link body 15 includes a plurality ofmembers (23 to 28) made of carbon fiber reinforced plastic, as will bedescribed later. The reaction link body 15 is configured by bonding theplurality of members (23 to 28) together into one unit, thus forming thepair of linear portions 19, the coupling portion 20, the fulcrum shaftattachment portion 21, and the actuator attachment portions 22 describedabove. Due to this configuration, the material constituting the pair oflinear portions 19 and the coupling portion 20 is fiber reinforcedplastic.

Note that the reaction link body 15 may be made of reinforced plasticother than carbon fiber-reinforced plastic described above. For example,the reaction link body 15 may be made of fiber reinforced plastics suchas glass fiber reinforced plastic, glass mat reinforced plastic, boronfiber reinforced plastic, aramid fiber reinforced plastic, polyethylenefiber reinforced plastic, and Zylon fiber reinforced plastic.

The pair of linear portions 19 of the reaction link body 15 are made upof a linear portion 19 a and a linear portion 19 b disposedsubstantially parallel to each other and each extending linearly. Thecoupling portion 20 is formed as a portion extending so as to connect toone end of each of the pair of linear portions 19 on the same side viabent portions (29 a, 29 b) and to couple those ends to each other. Notethat the coupling portion 20 is formed so as to extend in a directionsubstantially orthogonal to the linear portion 19 a and the linearportion 19 b, and the bent portions (29 a, 29 b) are formed as portionsthat are bent at substantially a right angle. Also, the coupling portion20 is formed so as to connect to one end of the linear portion 19 a viathe bent portion 29 a, to connect to one end of the linear portion 19 bvia the bent portion 29 b, and to couple those ends of the pair oflinear portions 19 a and 19 b to each other.

The fulcrum shaft attachment portion 21 of the reaction link body 15 isprovided so as to protrude from the center portion of the couplingportion 20 (the center portion in the direction in which the pair oflinear portions 19 are coupled) toward the control surface 102. Also,the fulcrum shaft attachment portion 21 is provided as a portion thatcan be attached pivotably via the bearing 16 to a fulcrum shaft 30 (seeFIG. 2) for rotatably supporting the control surface 102 with respect tothe body frame 101. Further, the fulcrum shaft attachment portion 21 isformed as a cylindrical portion integrated with the coupling portion 20and having a shorter axial length, and the outer ring of the bearing 16described above is fixed by fitting to the inner wall of the fulcrumshaft attachment portion 21. By providing the fulcrum shaft attachmentportion 21 and the bearing 16 in this way, the reaction link body 15 iscoupled pivotably to the control surface 102 at the fulcrum shaftattachment portion 21.

The actuator attachment portions 22 of the reaction link body 15 arerespectively provided as the other ends of the pair of linear portions19 that are opposite from the coupling portion 20. Also, the actuatorattachment portions 22 are made up of an actuator attachment portion 22a that is the other end of the linear portion 19 a and an actuatorattachment portion 22 b that is the other end of the linear portion 19b.

Further, a through hole is formed in each of the actuator attachmentportions (22 a, 22 b), and the bushes 17 are attached by fitting to thethrough holes. The bushes 17 are made up of a bush 17 a for being fixedto the actuator attachment portion 22 a and a bush 17 b for being fixedto the actuator attachment portion 22 b. The bushes 17 a and 17 b areeach formed in a cylindrical shape having a through hole through which apivot shaft 31, which will be described later, passes. Also, the bushes(17 a, 17 b) are each configured as a slidable member whose innerperimeter comes into slidable contact with the outer perimeter of thepivot shaft 31. Consequently, each of the actuator attachment portions(22 a, 22 b) is attached pivotably to the pivot shaft 31.

As shown in FIG. 1, the pivot shafts 31 described above are provided asa pair of cylindrical portions that are formed integrally with thecylinder body 13 at the other end of the cylinder body 13 of theactuator 11 (the side opposite from the side where the rod portion 14protrudes). Also, the pivot shafts 31 are formed so as to protrude inthe opposite directions from each other along the same straight line onboth lateral sides of the other end of the cylinder body 13. The pivotshafts 31 come into slidable contact with the bushes 17 and aresupported in a rotatable state. Consequently, the actuator attachmentportions (22 a, 22 b) of the reaction link body 15 are attachedpivotably to the other end of the actuator 11 via the bushes 17 and thepivot shafts 31. Thus, the reaction link body 12 is coupled pivotably tothe actuator 11 and the control surface 102.

Although a case where the pivot shafts 31 are formed integrally with thecylinder body 13 is described above as an example, this need not be thecase. For example, pivot shafts 31 that are each formed as a separatepart may be fixed to the cylinder body 13, or the other end of thecylinder body 13 may be attached rotatably to pivot shafts 31 that areeach provided as a separate part. Although this embodiment has beendescribed taking, as an example, the bushes 17 as elements for rotatablyholding the pivot shafts 31 relative to the actuator attachment portions22, this need not be the case. For example, bearings may be provided aselements for rotatably holding the pivot shafts 31 relative to theactuator attachment portions 22.

As described above, the reaction link body 15 is configured byintegrating the plurality of members (23 to 28) made of carbon fiberreinforced plastic into one unit. As the plurality of members (23 to28), a body member 23, coupling portion surface members (24, 25), acoupling portion end member 26, and linear portion end members (27, 28)are provided in the reaction link body 15.

The body member 23 is provided as a member constituting the basicskeleton of the pair of linear portions 19 and the coupling portion 20,and extending across the pair of linear portions 19 and the couplingportion 20. The body member 23 includes a pair of plate-like portions(23 a, 23 a) and a bridging portion 23 b, and is configured byintegrally forming these portions into one unit. The pair of plate-likeportions (23 a, 23 a) are each formed in a plate shape and are providedas a pair of portions that are arranged parallel to each other. Thebridging portion 23 b is provided as a portion that is connected,substantially perpendicularly, to one edge of each of the pair ofplate-like portions (23 a, 23 a) and that bridges the pair of plate-likeportions (23 a, 23 a) by coupling them. Accordingly, the cross sectionof the body member 23 that is perpendicular to the pair of plate-likeportions (23 a, 23 a) and the bridging portion 23 b is formed in across-sectional shape such as that of a square pipe one side of which isabsent and thus is open. Forming such a cross sectional shape enables aconfiguration that can ensure a large geometrical moment of inertia.

The pair of plate-like portions (23 a, 23 a) and the bridging portion 23b are provided so as to extend across the pair of linear portions 19 andthe coupling portion 20. The pair of plate-like portions 23 a aredisposed alongside each other in the thickness direction of the reactionlink body 15 (the direction indicated by the double-ended arrow C inFIG. 5). Note that the thickness direction of the reaction link body 15is defined as the direction that is perpendicular to both the widthdirection of the reaction link body 15 (the direction indicated by thedouble-ended arrow A in FIG. 4) and the longitudinal direction of thepair of linear portions 19 (19 a, 19 b) (the direction indicated by thedouble-ended arrow B in FIG. 4). The width direction of the reactionlink body 15 is defined as the direction in which the pair of linearportions 19 (19 a, 19 b) are disposed alongside each other.

The coupling portion surface members (24, 25) are each provided as aplate-like member having two portions extending in a curved manner, andare each disposed extending from the coupling portion 20 to one end ofeach of the pair of linear portions 19. Also, the coupling portionsurface member 24 and the coupling portion surface member 25 arerespectively disposed on opposite surfaces in the thickness direction ofthe reaction link body 15, and are disposed symmetrically with respectto the body member 23. These coupling portion surface members (24, 25)are respectively attached to the surfaces of the pair of plate-likeportions (23 a, 23 a) of the body member 23.

The coupling portion end member 26 includes a base portion 32constituting a part of the coupling portion 20, and the above-describedfulcrum shaft attachment portion 21 that is formed integrally with thebase portion 32 and that holds the bearing 16. The base portion 32 isdisposed along the coupling portion 20, and is formed in a block shapeprotruding so as to be tapered symmetrically in the width direction ofthe reaction link body 15 toward the control surface 102. Also, the baseportion 32 is attached to the body member 23 in a state in which it issandwiched between the pair of plate-like portions (23 a, 23 a). Thefulcrum shaft attachment portion 21 that is formed as a cylindricalportion having a shorter axial length and integrated with the tip end ofthe base portion 32 is disposed such that its axial direction (thedirection of the cylinder axis) is parallel to the width direction ofthe reaction link body 15.

The linear portion end members (27, 28) are provided as membersrespectively constituting the other ends of the pair of linear portions19. The linear portion end member 27 is provided so as to constitute theother end of the linear portion 19 a, and the linear portion end member28 is provided so as to constitute the other end of the linear portion19 b. Further, the linear portion end member 27 is provided with a bushholding portion in which a through hole for holding the bush 17 a isformed, and a pair of protruding portions formed in the shape of platesextending parallel to each other and protruding from the bush holdingportion in the longitudinal direction of the linear portion 19 a.Likewise, the linear portion end member 28 is provided with a bushholding portion in which a through hole for holding the bush 17 b isformed, and a pair of protruding portions formed in the shape of platesextending parallel to each other and protruding from the bush holdingportion in the longitudinal direction of the linear portion 19 b. Also,the pair of protruding portions of each of the linear portion end member(27, 28) are attached to the pair of plate-like portions (23 a, 23 a) ofthe body member 23 on opposite surfaces in the thickness direction ofthe reaction link body 15.

As clearly shown in FIGS. 3 to 5, the fastening members 18 each includea plurality of bolts 33, a plurality of nuts 34 that are respectivelyscrewed to the bolts 33, and a plurality of straight bushes 35, and areconfigured to bond the plurality of members (23 to 28) together into oneunit. By the bolts 33 and the nuts 34 of the fastening members 18 beingscrewed to each other, the plurality of members (23 to 28) are bondedtogether in a state in which they are disposed overlapping in thethickness of the reaction link body 15. Note that the straight bushes 35are each formed as a cylindrical member.

Of the plurality of bolts 33 (in this embodiment, eight bolts 33) of thefastening members 18, some of the bolts 33 (in this embodiment, fourbolts 33) are disposed alongside each other along the coupling portion20. Furthermore, the bolt shaft of each of the bolts 33 disposed alongthe coupling portion 20 extends along and passes through the couplingportion surface member 24, one of the pair of plate-like portions (23 a,23 a), the base portion 32 of the coupling portion end member 26, theother of the pair of plate-like portions (23 a, 23 a), and the couplingportion surface member 25. Also, the bolt head of each of theaforementioned bolts 33 abuts against the coupling portion surfacemember 24, and the opposite end of the bolt head protrudes from thecoupling portion surface member 25 and is screwed to each of the nuts34. Consequently, the plurality of members (23, 24, 25, 26) are disposedoverlapping in the thickness direction of the reaction link body 15 andare bonded together by the fastening members 18. Note that the couplingportion surface members (24, 25), the body member 23, and the couplingportion end member 26 are provided, for example, as members havingdifferent carbon fiber orientations in a direction perpendicular to thethickness direction of the reaction link body 15.

On the other hand, the remaining bolts 33 (in this embodiment, fourbolts 33) of the fastening members 18 are respectively disposed at theother ends of the pair of linear portions 19 (19 a, 19 b). The boltshaft of each of the bolts 33 disposed at the other end of the linearportion 19 a passes through the pair of protruding portions of thelinear portion end member 27, the pair of plate-like portions (23 a, 23a) of the body member 23, and the straight bushes 35. Also, the bolthead of each of the aforementioned bolts 33 abuts against one of thepair of protruding portions of the linear portion end member 27, and theopposite end of the bolt head protrudes from the other of the pair ofprotruding portions and is screwed to the nut 34.

Note that the straight bushes 35 are disposed between the pair ofplate-like portions (23 a, 23 a), with both of their ends in thedirection of the cylinder axis respectively abutting against the pair ofplate-like portions (23 a, 23 a). By the straight bushes 35, the pair ofplate-like portions (23 a, 23 a) are prevented from deformation thatcould be caused by fastening power exerted when the bolts 33 and thenuts 34 are screwed together.

As described above, the plurality of members (23, 27) are disposedoverlapping in the thickness direction of the reaction link body 15 andare bonded together by the fastening members 18 (33, 34, 35) disposed atthe other end of the linear portion 19 a. Further, the fastening members18 (33, 34, 35) disposed at the other end of the linear portion 19 b arealso provided for the reaction link body 15, as with the fasteningmembers 18 (33, 34, 35) disposed at the other end of the linear portion19 a. Also, the plurality of members (23, 28) are disposed overlappingin the thickness direction of the reaction link body 15 and are bondedtogether by the fastening members 18 (33, 34, 35). Note that the linearportion end members (27, 28) and the body member 23 are provided, forexample, as members having different carbon fiber orientations in adirection perpendicular to the thickness direction of the reaction linkbody 15.

Next, the actuation of the control surface drive unit 1 will bedescribed. When the control surface 102 is driven, a hydraulic system isactuated in accordance with an instruction from a controller (notshown), and pressure oil is supplied and discharged to and from thecylinder body 13 of the actuator 11. As a result ofsupplying/discharging pressure oil, the rod portion 14 is displaced suchthat it extends or contracts from or into the cylinder body 13.Consequently, the control surface 102 is driven at one end of the rodportion 14 of the actuator 11 that is pivotable about the pivot shafts31. At that time, one end of the reaction link body 15 is attachedpivotably to the fulcrum shaft 30 of the control surface 102 and theother end thereof is attached pivotably to the pivot shafts 31 asdescribed above, and therefore the control surface 102 is driven so asto pivot about the fulcrum shaft 30.

As described above, with the control surface drive unit (actuator-linkassembly) 1, in order to stably drive the control surface 102 viaactuation of the actuator 11, the reaction link (link) 12 is providedthat is formed in the shape of a portal including the pair of linearportions 19 and the coupling portion 20 coupling to the pair of linearportions 19 via the bent portions (29 a, 29 b). In the case of aconventional portal-shaped link that is made of a metallic material suchas a titanium alloy or stainless steel and that includes bent portions,it is difficult to realize further weight reduction, while ensuringstrength and rigidity in good balance. However, with the control surfacedrive unit 1, the pair of linear portions 19 and the coupling portion 20of the reaction link 12 are made of fiber reinforced plastic.Accordingly, it is possible to achieve a control surface drive unit 1that has a significantly smaller specific gravity (i.e., also has asignificantly smaller density), a significantly greater specificstrength and a significantly greater specific rigidity than thatachieved with a titanium alloy. Further, it is possible to achieve acontrol surface drive unit 1 that has a significantly greater specificstrength and a significantly greater specific rigidity than thatachieved with stainless steel. This makes it possible to ensure strengthand rigidity in good balance at a higher level and to realizesignificant weight reduction for a control surface drive unit(actuator-link assembly). Thus, it is possible, with this embodiment, torealize weight reduction for a control surface drive unit (actuator-linkassembly) including a portal-shaped reaction link, compared with theirconventional counterparts made of metals such as a titanium alloy andstainless steel, and to ensure strength and rigidity that are equal toor greater than those achieved with the counterparts.

[Actuator-Link Assembly Manufacturing Method, and Actuator-Link AssemblyDesigning Method]

Next, an actuator-link assembly manufacturing method according to thisembodiment and an actuator-link assembly designing method according tothis embodiment will be described. The actuator-link assemblymanufacturing method according to this embodiment constitutes amanufacturing method for manufacturing the actuator 11 and the reactionlink (link) 12 of the control surface drive unit 1. The actuator-linkassembly designing method according to this embodiment constitutes adesigning method for designing the actuator 11 and the reaction link(link) 12 of the control surface drive unit 1. Note that theactuator-link assembly manufacturing method according to this embodimentincludes the actuator-link assembly designing method according to thisembodiment as a constituting element.

FIG. 6 is a flowchart illustrating the actuator-link assemblymanufacturing method according to this embodiment (hereinafter, may alsobe simply referred to as the “manufacturing method of this embodiment”).As shown in FIG. 6, the manufacturing method of this embodiment includesa design process S101 constituting the actuator-link assembly designingmethod according to this embodiment (hereinafter, may also be simplyreferred to as the “designing method of this embodiment”), and aproduction process S102.

The design process S101 includes a material determining step S101 a, acomputing step S101 b, a rigidity determining step S101 c, and a shapedetermining step S101 d. The design process S101 is performed by adesigning apparatus 51 shown in FIG. 7 operating in accordance with aninput operation performed by a user (operator) (not shown) through aninput apparatus 52. FIG. 7 is a functional block diagram showing thedesigning apparatus 51, together with the input apparatus 52 and anoutput apparatus 53.

The designing apparatus 51 that performs the design process S101 isprovided as a computer apparatus capable of executing a program, andincludes a CPU (Central Processing Unit), a memory, an input/outputinterface, and so forth, which are not shown. In the designing apparatus51, a program that is stored on the memory and is configured to performthe design process S101 is read and executed by the CPU. Consequently,in the designing apparatus 51, a material determining portion 51 a thatperforms the material determining step S101 a, a computing portion 51 bthat performs the computing step S101 b, a rigidity determining portion51 c that performs the rigidity determining step S101 c, a shapedetermining portion 51 d that performs the shape determining step S101d, a display portion 51 e that causes the output apparatus 53 todisplay, for example, a computation result obtained by the computingportion 51 b, and so forth are constructed.

Further, the designing apparatus 51 is connected to the input apparatus52 and the output apparatus 53. The input apparatus 52 is an apparatusthrough which the user inputs an operation for the designing apparatus51. For example, the input apparatus 52 is provided as an input device,including, for example, a keyboard, and a pointing device such as amouse. The user can use the input apparatus 52 to input, into thedesigning apparatus 51, predetermined data required to perform thedesign process S101, and to operate the designing apparatus 51. Theoutput apparatus 53 is provided, for example, as a display apparatusincluding a display screen, and displays a result of processingperformed, for example, by the computing portion 51 b, in accordancewith the control performed by the display portion 51 e of the designingapparatus 51.

The material determining step S101 a of the design process S101 isconfigured as a step of determining the material constituting theactuator 11 and the material constituting the reaction link 12. In thematerial determining step S101 a, the material of the actuator 11 isdetermined to be stainless steel, for example. For the reaction link 12,for example, the material of the bearing 16 and the fastening members 18is determined to be stainless steel, the material of the bushes 17 isdetermined to be bronze, and the material of the reaction link body 15is determined to be carbon fiber reinforced plastic.

Since the materials are determined in the above-described manner, thematerial of the plurality of members (23 to 28) constituting thereaction link body 15 is determined to be carbon fiber reinforcedplastic, the material of the pair of linear portions 19 and the couplingportion 20 of the reaction link 12 is determined to be carbon fiberreinforced plastic. Note that the mode of the material determination inthe material determining step S101 a is not limited to theabove-described example, and the materials may be determined such thatat least one of the material constituting the actuator 11 and thematerial constituting the reaction link 12 contains fiber reinforcedplastic.

The computing step S101 b of the design process S101 is configured as astep of computing the change in gain margin with the change in arigidity ratio, which is the ratio of the rigidity of the reaction link12 to the rigidity of the actuator 11, using a computation modeldescribed below. The computation model used in the computing step S101 bis configured as a computation model that includes the inertial mass ofthe control surface 102, the rigidity of the control surface 102, therigidity of the actuator 11, the rigidity of the reaction link 12 asparameters, and that defines the relationship between the parameters.Note that the parameters of the inertial mass and rigidity of thecontrol surface 102 are input into the designing apparatus 51 by theuser operating the input apparatus 52, as data on inertial mass andrigidity that correspond to the control surface 102 to which the controlsurface drive unit 1 is applied. Likewise, data that are other than thedata on the inertial mass and the rigidity corresponding to the controlsurface 102 and that are required for computation performed in thecomputing step S101 b are also input into the designing apparatus 51 bythe user operating the input apparatus 52.

FIG. 8 is a diagram illustrating the computation model used in thecomputing step S101 b. As shown in FIG. 8, the computation model used inthe computing step S101 b is configured to define the relationshipbetween the parameters, as a spring-mass model in which the inertialmass M of the control surface 102, a spring having a spring constant Kc,which is obtained by modeling the rigidity of the control surface 102, aspring having a spring constant Kact, which is obtained by modeling therigidity of the actuator 11, and a spring having a spring constant Kr,which is obtained by modeling the rigidity of the reaction link 12, arecoupled in series. Further, in the computing step S101 b using thiscomputation model, computation is performed under a condition in whichoscillations are applied in the direction indicated by the double-endedarrow D in FIG. 8.

In the computing step S101 b, the change in gain margin with the changein the rigidity ratio (Kr/Kact), which is the ratio of the rigidity (Kr)of the reaction link 12 to the rigidity (Kact) of the actuator 11, iscomputed using the above-described computation model. FIG. 9 is a graphillustrating a computation result for the change in gain margin with thechange in the rigidity ratio (Kr/Kact). In FIG. 9, the longitudinal axisrepresents the gain margin, and the horizontal axis represents therigidity ratio (Kr/Kact) as a logarithmic axis. Note that the designingapparatus 51 is configured such that, for example, the computationresult shown in FIG. 9 is displayed to the output apparatus 53 inaccordance with the control performed by the display portion 51 e, andthat the user can confirm that computation result.

The rigidity determining step S101 c of the design process S101 isconfigured as a step of determining the rigidities of the actuator 11and the reaction link 12 such that the rigidity ratio (Kr/Kact) and thegain margin fall within their respective predetermined ranges, based onthe computation result obtained in the computing step S101 b. Forexample, the lower limit of the rigidity ratio (Kr/Kact) and the gainmargin in the above-mentioned predetermined ranges is set to 1.0 for therigidity ratio (Kr/Kact) and 18.0 for the gain margin so as to ensure ahigher rigidity and a higher gain margin than the control surface driveunit 1 in which the material of the actuator 11 is constituted bystainless steel and the material of the reaction link 12 is constitutedby a titanium alloy. For example, the upper limit of the rigidity ratio(Kr/Kact) and the gain margin in the above-mentioned predeterminedranges is set to 10.0 for the rigidity ratio (Kr/Kact) and 20.0 for thegain margin such that the range of the rigidity ratio (Kr/Kact) issmaller than a range in which the change in gain margin with an increasein the rigidity ratio (Kr/Kact) is substantially convergent and hencethe effect of further increasing the gain margin with an increase in theratio (Kr/Kact) (i.e., the effect of further increasing the controlstability) cannot be achieved (i.e., such that the range of the rigidityratio (Kr/Kact) is within a range that is expected to achieve the effectof increasing the control stability). In the rigidity determining stepS101 c, the rigidity ratio (Kr/Kact) and the gain margin are determinedto be certain values within the above-described predetermined rangesbased on predetermined conditions regarding, for example, the weight andthe strength, and moreover, the rigidity of the actuator 11 and therigidity of the reaction link 12 are determined based on that rigidityratio (Kr/Kact). For example, the designing apparatus 51 is configuredsuch that the rigidity values of the actuator 11 and the reaction link12 determined in the rigidity determining step S101 e can be displayedto the output apparatus 53 in accordance with the control performed bythe display portion 51 e, and that the user can confirm the result ofthis process.

FIG. 10 is a graph illustrating results of analyzing the relationshipbetween the weight (g) of the reaction link 12 and the rigidity ratio(Kr/Kact) for cases where the material of the actuator 11 is constitutedby stainless steel and the material of the reaction link 12 isconstituted by carbon fiber reinforced plastic, a titanium alloy, orstainless steel. Note that the analysis result for the case where thematerial constituting the reaction link 12 is carbon fiber reinforcedplastic is indicated by the solid line, the analysis result for the casewhere the material constituting the reaction link 12 is a titanium alloyis indicated by the broken line, and the analysis result for the casewhere the material constituting the reaction link 12 is stainless steelis indicated by the alternate long and short dash line. With regard tothe analysis results, calculations are carried out with the weight andthe rigidity ratio (Kr/Kact) being varied by varying the dimensionalrequirement on the thickness of the members (23 to 28) constituting thereaction link body 15. Further, the calculation conditions (lower limitconditions) that can ensure the lower limit strengths required as thereaction link 12 of the drive unit 1 for driving the control surface 102are indicated by the filled circles.

As shown in FIG. 10, when the material constituting the reaction link 12is carbon fiber reinforced plastic, it is possible to ensure strengththat is greater than or equal to that achieved when the materialconstituting the reaction link 12 is stainless steel or a titaniumalloy, and to ensure a higher rigidity, thus realizing furthersignificant weight reduction. Furthermore, as shown in FIG. 10, when thematerial constituting the reaction link 12 is carbon fiber reinforcedplastic, setting the rigidity ratio (Kr/Kact) to 1.0 or greater makes itpossible to achieve a higher rigidity and greater weight reduction thanthose achieved under the lower limit condition under which the greatestweight reduction is achieved using the titanium alloy as the materialconstituting the reaction link 12.

In the shape determining step S101 d of the design process S101, theshapes of the actuator 11 and the reaction link 12 are determined suchthat the rigidity of the actuator 11 and the rigidity of the reactionlink 12 are set to the rigidities determined in the rigidity determiningstep S101 c.

In the shape determining step S101 d, for example, the thicknessdimension of the cylinder portion of the cylinder body 13 and thediameter dimension of the shaft portion of the rod portion 14 aredetermined such that the rigidity of the actuator 11 is set to therigidity determined in the determining step S101 c, and thereby theshape of the actuator 11 is determined. Although a case where the shapeof the cylinder body 13 is set to be cylindrical and the shape of therod portion 14 is set to be a round bar shape having a circular crosssection is described as an example in this embodiment, this need not bethe case; the cross sectional shape may be set to be other crosssectional shapes. Further, the shape determining step S101 d may have amode in which a predetermined cross sectional shape is selected from aplurality of cross sectional shapes. In this case, for example, theshape determining step S101 d may have a mode in which a cross sectionalshape with which the rigidity determined in the rigidity determiningstep S101 b can be achieved with the smallest amount of the material(with the greatest weight reduction) is selected.

In the shape determining step S101 d, for example, the geometry of thereaction link 12, including, for example, the thickness dimension andthe width dimension of the members (23 to 28) of the reaction link body15, the diameter dimension of the bearing 16, and the diameter dimensionof the bushes 17 is determined such that the rigidity of the reactionlink 12 is set to the rigidity determined in the rigidity determiningstep S101 c, and thereby the shape of the reaction link 12 isdetermined. Although a case where the cross sectional shape of thereaction link body 15 is set to the predetermined cross sectional shapeshown in FIGS. 3 to 5 is described as an example in this embodiment,this need not be the case; it is possible to set a configuration havinganother cross sectional shape, such as a configuration having a squaretubular cross-sectional shape and a configuration having a plate-likecross sectional shape. Alternatively, a predetermined cross-sectionalshape may be selected from a plurality of cross-sectional shapes. Inthis case, for example, a cross-sectional shape with which the rigiditydetermined in the rigidity determining step S101 c can be achieved withthe smallest amount of the material (with the greatest weight reduction)may be selected. Note that the designing apparatus 51 is configured suchthat, for example, the shapes of the actuator 11 and the reaction link12 that have been determined in the shape determining step S101 d aredisplayed to the output apparatus 53 in accordance with the controlperformed by the display portion 51 e, and that the user can confirm theresult of this process.

The production process S102 includes a formation step S102 a and anassembly step S102 b. In the production process S102, the actuator 11and the reaction link 12 that have been designed in the design processS101 are produced.

The formation step S102 a of the production process S102 is configuredas a step of forming the actuator 11 and the reaction link 12 into theshapes determined in the shape determining step S101 d. In the formationstep S102 a, the cylindrical cylinder body 13 and the round bar-shapedrod portion 14 are processed with stainless steel into predeterminedshapes, and are assembled into one unit as the actuator 11.

In the formation step S102 a, the members (23 to 28) having thepredetermined shapes shown in FIGS. 3 to 5 are formed with carbon fiberreinforced plastic into predetermined geometries. Also, these members(23 to 28) are bonded together with the fastening members 18, and areintegrated into one unit as the reaction link body 15, and the bearing16 and the bushes 17 are also assembled to the reaction link body 15,thus forming the reaction link 12. Note that the operation of assemblingthe bearing 16 and the bushes 17 may be carried out before or in themiddle of the operation of bonding the members (23 to 28), instead ofbeing carried out after the bonding operation.

The assembly step S102 b of the production process S102 is configured asa step of coupling and assembling the actuator 11 and the reaction link12 that have been formed in the formation step S102 a. In the assemblystep S102 b, the pivot shafts 31 integrally formed with the cylinderbody 13 of the actuator 11 are inserted through the bushes 17 of thereaction link 12, and thereby the actuator 11 and the reaction link 12are coupled and assembled. Note that the formation step S102 a and theassembly step S102 b may be performed in parallel; for example, it ispossible to adopt a configuration in which the operation of insertingthe pivot shafts 31 through the bushes 17 is performed in the middle ofthe formation step S102 a and thereafter the formation of the reactionlink 12 is completed.

Finishing the production process S102 described above completes themanufacturing method of this embodiment shown in FIG. 6, thusmanufacturing the control surface drive unit (actuator-link assembly) 1shown in FIG. 1.

As described above, with the actuator-link assembly manufacturing methodaccording to this embodiment and the actuator-link assembly designingmethod according to this embodiment, the material constituting thereaction link 12 is determined such that it contains fiber reinforcedplastic. Accordingly, it is possible to achieve a control surface driveunit (actuator-link assembly) 1 that has a significantly smallerspecific gravity (i.e., also has a significantly smaller density), asignificantly greater specific strength and a significantly greaterspecific rigidity than that achieved with a titanium alloy. Further, itis possible to achieve a control surface drive unit (actuator-linkassembly) 1 that has a significantly greater specific strength and asignificantly greater specific rigidity than that achieved withstainless steel. Also, based on the computation result obtained usingthe computation model for the control surface 102, the actuator 11, andthe reaction link 12, the rigidities of the actuator 11 and the reactionlink 12 are determined such that the rigidity ratio (Kr/Kact) of thereaction link 12 to the actuator 11 and the gain margin fall withintheir respective predetermined ranges that have been set. Consequently,the rigidity of the control surface drive unit (actuator-link assembly)1 containing fiber reinforced plastic as the constituent material can bereliably determined to be a level capable of sufficiently suppressingdeformation and ensuring sufficient stability as the control system fordriving the control surface 102. Also, the design of the actuator 11 andthe reaction link 12 is completed upon determination of their shapessuch that the rigidities determined in the above described manner can beset. Furthermore, when the actuator 11 and the reaction link 12 areformed in the shapes determined in the above-described manner and arefurther coupled and assembled, the manufacture of the control surfacedrive unit (actuator-link assembly) 1 is completed. Thus, it is possibleto design and manufacture a control surface drive unit (actuator-linkassembly) 1 that can realize weight reduction compared with conventionalactuator-link assemblies made of metals such as a titanium alloy andstainless steel, and ensure strength and rigidity that are equal to orgreater than those achieved with such actuator-link assemblies.

Accordingly, with the actuator-link assembly manufacturing methodaccording to this embodiment, it is possible to design and manufacture acontrol surface drive unit (actuator-link assembly) 1 that can ensurestrength and rigidity that are equal to or greater than those achievedwith conventional actuator-link assemblies, and realize further weightreduction.

Furthermore, with the actuator-link assembly designing method accordingto this embodiment, in order to stably drive the control surface 102 viaactuation of the actuator 11, the reaction link 12 is designed that isformed in the shape of a portal including the pair of linear portions 19and the coupling portion 20 coupling to the pair of linear portions 19via the bent portions (29 a, 29 b). In the case of a portal-shapedreaction link including bent portions, it is difficult to realize weightreduction, while ensuring strength and rigidity in good balance.However, with the designing method of this embodiment, the materialconstituting the pair of linear portions 19 and the coupling portion 20of the reaction link 12 is determined to be fiber reinforced plastic,and therefore it is possible to ensure strength and rigidity in goodbalance at a higher level, and to realize significant weight reduction.

Furthermore, with the actuator-link assembly designing method accordingto this embodiment, the computation model used in the computing stepS101 b is configured for the control surface 102, the actuator 11 andthe reaction link 12 as a spring-mass model in which the inertial massand the springs thereof are coupled in series. Accordingly, acomputation model for more accurately defining the relationship betweenthe parameters of the inertial mass M of the control surface 102, therigidity (spring constant Kc) of the control surface 102, the rigidity(spring constant Kact) of the actuator 11, and the rigidity (springconstant Kr) of the reaction link 12 can be achieved with a simplecomputation model, based on the actual relationship between the controlsurface 102, the actuator 11, and the reaction link 12 that are coupledin series.

Although an embodiment of the present invention has been described thusfar, the present invention is not limited to the above-describedembodiment, and various modifications may be made within the scoperecited in the claims. For example, the following modifications arepossible.

(1) Although this embodiment has been described, taking as an example, aconfiguration in which the material constituting the link contains fiberreinforced plastic, this need not be the case. That is, it is possibleto adopt a configuration in which only the material constituting theactuator contains fiber reinforced plastic, or a configuration in whichboth the material constituting the link and the material constitutingthe actuator contain fiber reinforced plastic.

(2) The shapes of the actuator and the reaction link are not limited tothose illustrated in this embodiment, and various modifications may bemade. Furthermore, the present invention may be applied to a link havinga configuration other than that of the reaction link illustrated in thisembodiment.

The present invention can be applied widely to an actuator-link assemblyincluding an actuator that can be attached to a control surface of anaircraft or to a horn arm member in order to drive the control surface,and a link that is coupled to that actuator, a manufacturing method formanufacturing the actuator-link assembly, and a designing method fordesigning the actuator-link assembly. The present invention is notlimited to the above-described embodiment, and all modifications,applications and equivalents thereof that fall within the claims, forwhich modifications and applications would become apparent by readingand understanding the present specification, are intended to be embracedtherein.

What is claimed is:
 1. An actuator-link assembly manufacturing methodfor manufacturing an actuator that can be attached pivotably, at one endthereof, to a control surface of an aircraft or to a horn arm memberattached to the control surface in order to drive the control surface,and a link that is coupled to the actuator, the method comprising: amaterial determining step of determining a material constituting theactuator and a material constituting the link; a computing step ofcomputing a change in gain margin with a change in a rigidity ratio,which is the ratio of the rigidity of the link to the rigidity of theactuator, using a computation model that includes an inertial mass ofthe control surface, a rigidity of the control surface, a rigidity ofthe actuator, and a rigidity of the link as parameters and that definesa relationship between the parameters; a rigidity determining step ofdetermining rigidities of the actuator and the link such that therigidity ratio and the gain margin fall within respective predeterminedranges, based on a computation result obtained in the computing step; ashape determining step of determining shapes of the actuator and thelink such that rigidities of the actuator and the link are set to therigidities determined in the rigidity determining step; a formation stepof forming the actuator and the link into the shapes determined in theshape determining step; and an assembly step of coupling and assemblingthe actuator and the link formed in the formation step, wherein the linkis attached pivotably to a fulcrum shaft for rotatably supporting thecontrol surface, and is also attached pivotably to the other end of theactuator via a pivot shaft, and, in the material determining step, thematerials are determined such that at least one of the materialconstituting the actuator and the material constituting the linkcontains fiber reinforced plastic.
 2. An actuator-link assemblydesigning method for designing an actuator that can be attachedpivotably, at one end thereof, to a control surface of an aircraft or toa horn arm member attached to the control surface in order to drive thecontrol surface, and a link that is coupled to the actuator, the methodcomprising: a material determining step of determining a materialconstituting the actuator and a material constituting the link; acomputing step of computing a change in gain margin with a change in arigidity ratio, which is the ratio of the rigidity of the link to therigidity of the actuator, using a computation model that includes aninertial mass of the control surface, a rigidity of the control surface,a rigidity of the actuator, and a rigidity of the link as parameters andthat defines a relationship between the parameters; a rigiditydetermining step of determining rigidities of the actuator and the linksuch that the rigidity ratio and the gain margin fall within respectivepredetermined ranges, based on a computation result obtained in thecomputing step; and a shape determining step of determining shapes ofthe actuator and the link such that rigidities of the actuator and thelink are set to the rigidities determined in the rigidity determiningstep, wherein the link is attached pivotably to a fulcrum shaft forrotatably supporting the control surface, and is also attached pivotablyto the other end of the actuator via a pivot shaft, and, in the materialdetermining step, the materials are determined such that at least one ofthe material constituting the actuator and the material constituting thelink contains fiber reinforced plastic.
 3. The actuator-link assemblydesigning method according to claim 2, wherein the link comprises: apair of linear portions disposed alongside each other and each extendinglinearly; a coupling portion connecting to one end of each of the pairof linear portions on the same side via a bent portion and extending soas to couple the one end of each of the pair of linear portions on thesame side to each other; a fulcrum shaft attachment portion that isprovided so as to protrude from a center portion of the coupling portionand that can be attached pivotably to a fulcrum shaft for rotatablysupporting the control surface; and an actuator attachment portion thatis provided as the other end of each of the pair of linear portions andthat can be attached pivotably to the other end of the actuator via apivot shaft, and, in the material determining step, the materials aredetermined such that a material constituting the pair of linear portionsand the coupling portion contains fiber reinforced plastic.
 4. Theactuator-link assembly designing method according to claim 2, whereinthe computation model used in the computing step defines a relationshipbetween the parameters, as a spring-mass model in which the inertialmass of the control surface, a spring obtained by modeling the rigidityof the control surface, a spring obtained by modeling the rigidity ofthe actuator, and a spring obtained by modeling the rigidity of the linkare coupled in series.